Svelte example: upgrade from Svelte 4 to Svelte 5 runes

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This PR contains:

• A BUGFIX
• IMPROVED TESTS
• IMPROVED DOCS
• Dependency upgrade of examples/svelte

Describe the problem you have without this PR

examples/svelte was pinned to svelte@4.2.20. Svelte 5 has been the current major version since October 2024, so the example showed patterns that no longer match what a new Svelte app looks like: new App({ target }), svelte/store writables with $store auto-subscriptions, on:click handlers and a self-closing <textarea /> (which Svelte 5 rejects).

While migrating, the edit path turned out to be broken. NoteEditor called RxDocument.update() but store.js only added the query-builder and dev-mode plugins, so saving an already existing note threw you must add the update plugin. The old e2e test is named insert/edit/remove a note but never actually edited a note, so nothing caught it.

What changed

Svelte 5 migration

• svelte 4.2.20 -> 5.56.8, plus runes: true in the compiler options of rollup.config.mjs so the example cannot fall back to legacy reactivity. rollup-plugin-svelte@7.2.3 already supports Svelte 5 and compiles .svelte.js rune modules, so the build setup stays as it is.
• src/main.js mounts with mount(App, { target }) instead of new App({ target }).
• src/store.js -> src/store.svelte.js. The four writables are replaced by one $state object plus selectNote() and resetForm() helpers. Components read and bind: to its fields directly, no $ prefix and no .set() calls.
• NoteList.svelte subscribes to the RxDB query inside an $effect and returns a teardown that unsubscribes. The old onMount version never unsubscribed. The {#await} block around a plain array was replaced by a real loaded flag, and the {#each} is now keyed by the primary key.
• on:click -> onclick, <textarea /> -> <textarea></textarea>.
• Removed scripts/setupTypeScript.js, a leftover of the old sveltejs/template that pinned svelte-check@2 and svelte-preprocess@4. Nothing referenced it and both are incompatible with Svelte 5.

Bugfix

• NoteEditor now uses the core incrementalPatch() instead of update(). It needs no extra plugin and retries on conflicts.
• The title input is readonly while an existing note is edited, because name is the primaryKey of the schema and cannot change. Before this, editing the title of a saved note would have thrown even with the update plugin added.

Todos

• Tests: added an e2e testcase that inserts a note, selects it, changes the body and verifies the note was updated instead of inserted twice. Verified npm run build plus the full e2e suite (2 passed) against a Chrome 141 headless run, and checked that all components and the rune module compile without warnings in dev: true, runes: true mode.
• Documentation: examples/svelte/README.md lists where the runes are used.
• Typings: not affected, the example is plain JavaScript.
• Changelog: orga/changelog/svelte-example-svelte-5-runes.md